Rocket engines are arranged to combust at least one propellant, and commonly are arranged as a bi-propellant system including a fuel and an oxidizer.
One known type of rocket propulsion system includes a fuel tank and an oxidizer tank configured to store propellant at a relatively low pressure. This type of system further includes a turbopump, including a turbine in communication with at least one pump. In one example, after the initial start-up of the system, the main combustion phase is sustained by the turbine being driven by exhaust from a gas generator (e.g., a gas-generator cycle). In another example, the turbine is driven by a fluid heated in a heat exchanger (e.g., an expander cycle) to sustain the main combustion phase.
In another known rocket engine, propellant is stored at a relatively high pressure in one or more storage tanks. The propellant is then selectively released from the storage tanks and provided to the combustion chamber without being pressurized by a turbopump.